This invention relates to novel inhibitors of androgen activity, for example to non-steroidal compounds having antagonistic activity on androgen receptor. More particularly, the invention relates to certain non-steroidal compounds having specified side-chains (e.g. containing a pyridyl moiety) which interact with the helix 12 of the androgen receptor, and metabolites thereof which block androgen action by acting, among other mechanisms, through the androgen receptor, while not activating such receptor in some or all androgen-sensitive tissues. Some compounds of the invention are Selective Androgen Receptor Modulators (SARMs) which have desirable antagonistic activity in some tissues (e.g. prostate) while exhibiting desirable agonistic activity in other tissues (e.g. muscle, sexual function . . . ).